diff --git a/shell/ash.c b/shell/ash.c
index f631e3d25..c27ab7de2 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -5442,22 +5442,21 @@ redirectsafe(union node *redir, int flags)
 static arith_t
 ash_arith(const char *s)
 {
-	arith_eval_hooks_t math_hooks;
+	arith_state_t math_state;
 	arith_t result;
-	int errcode = 0;
 
-	math_hooks.lookupvar = lookupvar;
-	math_hooks.setvar    = setvar2;
-	//math_hooks.endofname = endofname;
+	math_state.lookupvar = lookupvar;
+	math_state.setvar    = setvar2;
+	//math_state.endofname = endofname;
 
 	INT_OFF;
-	result = arith(s, &errcode, &math_hooks);
-	if (errcode < 0) {
-		if (errcode == -3)
+	result = arith(&math_state, s);
+	if (math_state.errcode < 0) {
+		if (math_state.errcode == -3)
 			ash_msg_and_raise_error("exponent less than 0");
-		if (errcode == -2)
+		if (math_state.errcode == -2)
 			ash_msg_and_raise_error("divide by zero");
-		if (errcode == -5)
+		if (math_state.errcode == -5)
 			ash_msg_and_raise_error("expression recursion loop detected");
 		raise_error_syntax(s);
 	}
diff --git a/shell/hush.c b/shell/hush.c
index ef0c454ec..4ca5403de 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -4463,15 +4463,16 @@ static char *encode_then_expand_string(const char *str, int process_bkslash, int
 #if ENABLE_SH_MATH_SUPPORT
 static arith_t expand_and_evaluate_arith(const char *arg, int *errcode_p)
 {
-	arith_eval_hooks_t hooks;
+	arith_state_t math_state;
 	arith_t res;
 	char *exp_str;
 
-	hooks.lookupvar = get_local_var_value;
-	hooks.setvar = set_local_var_from_halves;
-	//hooks.endofname = endofname;
+	math_state.lookupvar = get_local_var_value;
+	math_state.setvar = set_local_var_from_halves;
+	//math_state.endofname = endofname;
 	exp_str = encode_then_expand_string(arg, /*process_bkslash:*/ 1, /*unbackslash:*/ 1);
-	res = arith(exp_str ? exp_str : arg, errcode_p, &hooks);
+	res = arith(&math_state, exp_str ? exp_str : arg);
+	*errcode_p = math_state.errcode;
 	free(exp_str);
 	return res;
 }
diff --git a/shell/math.c b/shell/math.c
index a9fbc8910..555559a26 100644
--- a/shell/math.c
+++ b/shell/math.c
@@ -119,10 +119,9 @@
 #include "libbb.h"
 #include "math.h"
 
-#define a_e_h_t   arith_eval_hooks_t
-#define lookupvar (math_hooks->lookupvar)
-#define setvar    (math_hooks->setvar   )
-//#define endofname (math_hooks->endofname)
+#define lookupvar (math_state->lookupvar)
+#define setvar    (math_state->setvar   )
+//#define endofname (math_state->endofname)
 
 typedef unsigned char operator;
 
@@ -249,13 +248,12 @@ typedef struct chk_var_recursive_looped_t {
 static chk_var_recursive_looped_t *prev_chk_var_recursive;
 
 static int
-arith_lookup_val(v_n_t *t, a_e_h_t *math_hooks)
+arith_lookup_val(arith_state_t *math_state, v_n_t *t)
 {
 	if (t->var) {
 		const char *p = lookupvar(t->var);
 
 		if (p) {
-			int errcode;
 			chk_var_recursive_looped_t *cur;
 			chk_var_recursive_looped_t cur_save;
 
@@ -273,10 +271,10 @@ arith_lookup_val(v_n_t *t, a_e_h_t *math_hooks)
 			cur_save.next = cur;
 			prev_chk_var_recursive = &cur_save;
 
-			t->val = arith(p, &errcode, math_hooks);
+			t->val = arith(math_state, p);
 			/* restore previous ptr after recursion */
 			prev_chk_var_recursive = cur;
-			return errcode;
+			return math_state->errcode;
 		}
 		/* allow undefined var as 0 */
 		t->val = 0;
@@ -288,13 +286,13 @@ arith_lookup_val(v_n_t *t, a_e_h_t *math_hooks)
  * stack. For an unary operator it will only change the top element, but a
  * binary operator will pop two arguments and push the result */
 static NOINLINE int
-arith_apply(operator op, v_n_t *numstack, v_n_t **numstackptr, a_e_h_t *math_hooks)
+arith_apply(arith_state_t *math_state, operator op, v_n_t *numstack, v_n_t **numstackptr)
 {
 #define NUMPTR (*numstackptr)
 
 	v_n_t *numptr_m1;
 	arith_t numptr_val, rez;
-	int ret_arith_lookup_val;
+	int err;
 
 	/* There is no operator that can work without arguments */
 	if (NUMPTR == numstack)
@@ -302,9 +300,9 @@ arith_apply(operator op, v_n_t *numstack, v_n_t **numstackptr, a_e_h_t *math_hoo
 	numptr_m1 = NUMPTR - 1;
 
 	/* Check operand is var with noninteger value */
-	ret_arith_lookup_val = arith_lookup_val(numptr_m1, math_hooks);
-	if (ret_arith_lookup_val)
-		return ret_arith_lookup_val;
+	err = arith_lookup_val(math_state, numptr_m1);
+	if (err)
+		return err;
 
 	rez = numptr_m1->val;
 	if (op == TOK_UMINUS)
@@ -339,9 +337,9 @@ arith_apply(operator op, v_n_t *numstack, v_n_t **numstackptr, a_e_h_t *math_hoo
 		numptr_m1 = NUMPTR - 1;
 		if (op != TOK_ASSIGN) {
 			/* check operand is var with noninteger value for not '=' */
-			ret_arith_lookup_val = arith_lookup_val(numptr_m1, math_hooks);
-			if (ret_arith_lookup_val)
-				return ret_arith_lookup_val;
+			err = arith_lookup_val(math_state, numptr_m1);
+			if (err)
+				return err;
 		}
 		if (op == TOK_CONDITIONAL) {
 			numptr_m1->contidional_second_val = rez;
@@ -490,7 +488,7 @@ endofname(const char *name)
 }
 
 arith_t
-arith(const char *expr, int *perrcode, a_e_h_t *math_hooks)
+arith(arith_state_t *math_state, const char *expr)
 {
 	operator lasttok;
 	int errcode;
@@ -543,7 +541,7 @@ arith(const char *expr, int *perrcode, a_e_h_t *math_hooks)
 			}
 			if (numstack->var) {
 				/* expression is $((var)) only, lookup now */
-				errcode = arith_lookup_val(numstack, math_hooks);
+				errcode = arith_lookup_val(math_state, numstack);
 			}
 			goto ret;
 		}
@@ -658,7 +656,7 @@ arith(const char *expr, int *perrcode, a_e_h_t *math_hooks)
 						break;
 					}
 				}
-				errcode = arith_apply(prev_op, numstack, &numstackptr, math_hooks);
+				errcode = arith_apply(math_state, prev_op, numstack, &numstackptr);
 				if (errcode)
 					goto ret;
 			}
@@ -675,7 +673,7 @@ arith(const char *expr, int *perrcode, a_e_h_t *math_hooks)
  err:
 	numstack->val = errcode = -1;
  ret:
-	*perrcode = errcode;
+	math_state->errcode = errcode;
 	return numstack->val;
 }
 
diff --git a/shell/math.h b/shell/math.h
index 96088b4d2..9f3da7f59 100644
--- a/shell/math.h
+++ b/shell/math.h
@@ -9,61 +9,59 @@
 
 /* The math library has just one function:
  *
- *	arith_t arith(const char *expr, int *perrcode, arith_eval_hooks_t *hooks);
+ * arith_t arith(arith_state_t *states, const char *expr);
  *
- *	The first argument is the math string to parse.  All normal expansions must
- *	be done already.  i.e. no dollar symbols should be present.
+ * The expr argument is the math string to parse.  All normal expansions must
+ * be done already.  i.e. no dollar symbols should be present.
  *
- *	The second argument is a semi-detailed error description in case something
- *	goes wrong in the parsing steps.  Currently, those values are (for
- *	compatibility, you should assume all negative values are errors):
- *		 0 - no errors (yay!)
- *		-1 - unspecified problem
- *		-2 - divide by zero
- *		-3 - exponent less than 0
- *		-5 - expression recursion loop detected
+ * The state argument is a pointer to a struct of hooks for your shell (see below),
+ * and a semi-detailed error code. Currently, those values are (for
+ * compatibility, you should assume all negative values are errors):
+ * 0 - no errors (yay!)
+ * -1 - unspecified problem
+ * -2 - divide by zero
+ * -3 - exponent less than 0
+ * -5 - expression recursion loop detected
  *
- *	The third argument is a struct pointer of hooks for your shell (see below).
- *
- *	The function returns the answer to the expression.  So if you called it
- *	with the expression:
- *		"1 + 2 + 3"
- *	You would obviously get back 6.
+ * The function returns the answer to the expression.  So if you called it
+ * with the expression:
+ * "1 + 2 + 3"
+ * you would obviously get back 6.
  */
 
 /* To add support to a shell, you need to implement three functions:
  *
- *	lookupvar() - look up and return the value of a variable
+ * lookupvar() - look up and return the value of a variable
  *
- *		If the shell does:
- *			foo=123
- *		Then the code:
- *			const char *val = lookupvar("foo");
- *		Will result in val pointing to "123"
+ *	If the shell does:
+ *		foo=123
+ *	Then the code:
+ *		const char *val = lookupvar("foo");
+ *	will result in val pointing to "123"
  *
- *	setvar() - set a variable to some value
+ * setvar() - set a variable to some value
  *
- *		If the arithmetic expansion does something like:
- *			$(( i = 1))
- *		Then the math code will make a call like so:
- *			setvar("i", "1", 0);
- *		The storage for the first two parameters are not allocated, so your
- *		shell implementation will most likely need to strdup() them to save.
+ *	If the arithmetic expansion does something like:
+ *		$(( i = 1))
+ *	then the math code will make a call like so:
+ *		setvar("i", "1", 0);
+ *	The storage for the first two parameters are not allocated, so your
+ *	shell implementation will most likely need to strdup() them to save.
  *
- *	endofname() - return the end of a variable name from input
+ * endofname() - return the end of a variable name from input
  *
- *		The arithmetic code does not know about variable naming conventions.
- *		So when it is given an experession, it knows something is not numeric,
- *		but it is up to the shell to dictate what is a valid identifiers.
- *		So when it encounters something like:
- *			$(( some_var + 123 ))
- *		It will make a call like so:
- *			end = endofname("some_var + 123");
- *		So the shell needs to scan the input string and return a pointer to the
- *		first non-identifier string.  In this case, it should return the input
- *		pointer with an offset pointing to the first space.  The typical
- *		implementation will return the offset of first char that does not match
- *		the regex (in C locale): ^[a-zA-Z_][a-zA-Z_0-9]*
+ *	The arithmetic code does not know about variable naming conventions.
+ *	So when it is given an experession, it knows something is not numeric,
+ *	but it is up to the shell to dictate what is a valid identifiers.
+ *	So when it encounters something like:
+ *		$(( some_var + 123 ))
+ *	It will make a call like so:
+ *		end = endofname("some_var + 123");
+ *	So the shell needs to scan the input string and return a pointer to the
+ *	first non-identifier string.  In this case, it should return the input
+ *	pointer with an offset pointing to the first space.  The typical
+ *	implementation will return the offset of first char that does not match
+ *	the regex (in C locale): ^[a-zA-Z_][a-zA-Z_0-9]*
  */
 
 /* To make your life easier when dealing with optional 64bit math support,
@@ -96,13 +94,14 @@ typedef const char* FAST_FUNC (*arith_var_lookup_t)(const char *name);
 typedef void        FAST_FUNC (*arith_var_set_t)(const char *name, const char *val);
 //typedef const char* FAST_FUNC (*arith_var_endofname_t)(const char *name);
 
-typedef struct arith_eval_hooks {
+typedef struct arith_state_t {
 	arith_var_lookup_t    lookupvar;
 	arith_var_set_t       setvar;
 //	arith_var_endofname_t endofname;
-} arith_eval_hooks_t;
+	int                   errcode;
+} arith_state_t;
 
-arith_t arith(const char *expr, int *perrcode, arith_eval_hooks_t*);
+arith_t arith(arith_state_t *state, const char *expr);
 
 POP_SAVED_FUNCTION_VISIBILITY